Water Treatment Class 3-A Practice Test

Color observed in a water sample that includes the effects of both dissolved substances and suspended matter is described as apparent color. This is the color you see in a raw sample because both dissolved colorants (like humic substances or iron) and light interaction with suspended particles contribute to what’s measured.

In contrast, true color refers to color from dissolved substances only, determined after removing suspended matter (often by filtration). Turbidity is about how cloudy the water is due to suspended particles and doesn’t directly measure color. Color index is a separate metric used for standardizing or comparing colors, not specifically the combined color contribution from dissolved substances and suspended matter.

So, the term that accounts for color from both dissolved substances and suspended matter is apparent color.